Literature Review of Hydrometallurgical Recycling of Printed Circuit Boards (PCBs)

This study provides an up-to-date review of recycling of printed circuit boards (PCBs), specifically in hydrometallurgical treatment. Waste printed circuit boards, which are rich in base and precious metals, are the essential component of end-of-life electrical and electronic equipment.

From the economic and environmental perspectives, the efficient recycling of PCBs is of importance. For the extraction of metals from PCBs, a large amount of work has been done to establish an environmentally friendly and economic way to recover metals from PCBs based on physical, pyrometallurgical and hydrometallurgical processes.

Among those processes, hydrometallurgy is a promising treatment due to its low capital cost, high selectivity and lower environmental impact. This review emphasizes the recycling of PCBs by physical and hydrometallurgical treatments.

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Foundations of Chemical Kinetic Modeling, Reaction Models and Reactor Scale-Up

Even today, unfortunately, the industrial professional performing the design of a chemical reactor may not have the practical experience in Mathematics as well as Quantum Mechanics or Physical Chemistry to fully understand the implications of the mathematical formulism.

This is especially true of the mathematical methods used in Quantum Chemistry as well as quantum mechanics applications to the estimate of rates of chemical reactions.

Another important consideration that may be difficult during the composition of reaction models is the generation of elementary chemical reactions to explain the formation of products and most important trace components some of which may be of concern due to pollution of the environment.

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Supercritical and Superheated Technologies: Future of Biodiesel Production

Awareness on global warming has led to greater emphasis on renewable energy as the next source of energy. Renewable energy sources such as biofuels, wind energy, hydroelectric power, geothermal and solar powers are the solutions for the world not to be excessively dependent on fossil fuels.

These renewable energy sources do not emit excessive harmful gases or particulates to the environmental. Instead, it has the potential to mitigate climate change and solve environmental pollution. Among these renewable energy sources, biofuels particularly biodiesel has been anticipated as the best alternative energy source in transportation sector.

Biodiesel has been receiving high attention from worldwide researchers because biodiesel is a good replacement fuels for fossil fuels. Biodiesel has low carbon emission and thus has minimal impact on environment. In addition, it also has similar chemical structure and energy content with fossil fuels.

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Biochemical Pathology in an Experimental Second-Hand Cigarette Smoke Exposure Model

White matter injury and degeneration are common features of developmental and aging-associated diseases, yet their pathobiological bases are poorly understood. However, recent advances in Matrix-Assisted Laser Desorption Ionization instruments and chemistry have provided critical tools for myelin-lipid analytical research.

This study characterizes Cigarette Smoke exposure effects on frontal lobe lipid ion profiles in adult male A/J mice that had been exposed to air for 8 weeks (A8), CS for 4 (CS4) or 8 weeks , or CS8 followed by 2 weeks recovery. MALDI data acquired by analysis of lipid extracts plated onto a ground steel target (high through-put) were compared with Imaging Mass Spectrometry.

MALDI-time-of-flight detected 120 lipid ions with m/z’s of 600 to 1300 (phospholipids and sulfatides) in samples plated onto the steel target or analyzed by IMS, but just 25 ions (18%) were detected by both methods.

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Deoxygenation of Palmitic Acid to Produce Diesel-like Hydrocarbons over Nickel Incorporated Cellular Foam Catalyst

Nickel incorporated mesostructured cellular foam (NiMCF) was studied as a catalyst for palmitic acid deoxygenation to primarily synthesize n-pentadecane and 1-pentadecene. The kinetic behaviour was tested in a temperature range from 280 to 300°C.

The reaction was found to follow a first order kinetic model with respect to the palmitic acid with an activation energy of 111.57 KJ/Mol. In the reusability study, it was found that the average reduction in palmitic acid conversions was about 40.5%, which indicated the occurrence of catalyst deactivation during the deoxygenation. Fresh and spent catalysts were characterized by means of scanning electron microscope.

Energy-dispersive X-ray spectroscopy and X-ray powder diffraction correlate their characteristics with catalytic activity and to identify the main catalyst deactivation mechanism. The catalyst deactivation was mainly due to phase transformation of metallic nickel (Ni0) to nickel ion (Ni2+) and the deposition of organic molecules on the catalyst during the deoxygenation.

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Comprehensive Isotopic and Elemental Analysis of a Multi-Oxide Glass By Multicollector ICP-MS in Isotope Substitution Studies

Multicollector ICP-MS was used to comprehensively analyze different types of isotopically modified glass created to investigate the processes of glass corrosion in the water.

Analytical methods were developed for the analyses of synthesized, isotopically modified solid glass and the release of glass constituents upon contact with deionized water. To validate the methods, results from an acid digestion sample of the Analytical Reference Glass showed good agreement when compared to data from multiple prior analyses on the same glass.

In this paper, we present the results of the comprehensive analysis of the acid digestion of six types of isotopically modified glass and the release of glass constituents into water corrosion after one year of aqueous corrosion.

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Literature Review of Hydrometallurgical Recycling of Printed Circuit Boards

This study provides an up-to-date review of recycling of printed circuit boards (PCBs), specifically in hydrometallurgical treatment. Waste printed circuit boards, which are rich in base and precious metals, are the essential component of end-of-life electrical and electronic equipment.

From the economic and environmental perspectives, the efficient recycling of PCBs is of importance. For the extraction of metals from PCBs, a large amount of work has been done to establish an environmentally friendly and economic way to recover metals from PCBs based on physical, pyrometallurgical and hydrometallurgical processes.

Among those processes, hydrometallurgy is a promising treatment due to its low capital cost, high selectivity and lower environmental impact. This review emphasizes the recycling of PCBs by physical and hydrometallurgical treatments.

PDF LINK